Silicone rubber seals are the perfect exterior and interior  window seals as they are UV stable, and have excellent resistance against ozone and weathering.  Easily pigmentable, silicone extrusions can be used as a design feature of the building.  In other areas, silicone extrusions can be used to seal between metal or concrete panels. For sensitive areas such us underground stations, specialist compounds can be used which are low smoke/ low toxic.